On Tue, Feb 14, 2017 at 11:05 AM, Bin Cheng <bin.ch...@arm.com> wrote: > Hi, > This is the second try fixing PR71437. The old version patch tried to fix > issue in VRP but it requires further non-trivial change in VRP, specifically, > to better support variable value ranges. This is not appropriate at stage 4. > Alternatively, this patch tries to fix issue by improving threading. It > additionally simplifies condition by using assertion conditions. > > Bootstrap and test on x86_64 and AArch64. Is it OK?
Hmm. So I'm not a big fan of tree_simplify_using_condition ;) The case in question for the PR was an equivalent assert to the condition? Thus basically tree_simplify_using_condition (x <= 52, x <= 25)? + if (is_gimple_assign (def0) + && TREE_CODE (gimple_assign_rhs1 (def0)) == ASSERT_EXPR) gimple_assign_rhs_code (def0) == ASSERT_EXPR As you add a parameter to tree_simplify_using_condition you can as well fold it into tree_simplify_using_condition_1. And ideally I'd like to see us pass in a decomposed toplevel expression to avoid + tree res = fold_build2 (cond_code, boolean_type_node, + assert_op0, assert_op1); but I'm not sure that will work out ;) So, in the end I wonder if we can fix this in threading w/o usign tree_simplify_using_conditon (the main issue with it I have is the extensive tree building it does). Richard. > Thanks, > bin > > 2017-02-13 Bin Cheng <bin.ch...@arm.com> > > PR tree-optimization/71437 > * tree-ssa-loop-niter.c (tree_simplify_using_condition): Only > expand condition if new parameter says so. Also change it to > global. > * tree-ssa-loop-niter.h (tree_simplify_using_condition): New > declaration. > * tree-ssa-threadedge.c (tree-ssa-loop-niter.h): New include file. > (simplify_control_stmt_condition_1): Simplify condition using > assert conditions. > > gcc/testsuite/ChangeLog > 2017-02-13 Bin Cheng <bin.ch...@arm.com> > > PR tree-optimization/71437 > * gcc.dg/tree-ssa/pr71437.c: New test.
